When articles are subjected to heat treatment in a furnace, or heated in the furnace for degreasing, organic substances are evaporated from them into the furnace. These substances include oily gases and poisonous gases containing dioxin. Such gases which pollute the air and environment, have to be reduced before they are exhausted.
Accordingly, this invention relates to a method for reducing pollutional substances from gases evaporated from articles heated in a furnace, and it relates also to a furnace which can advantageously perform such method.
It is widely known that before gases which have been evaporated into a furnace from articles heated in the furnace, are exhausted into the air, they are led by a pipe into a combustion column which is located outside the furnace, and from which they are released into the air after they have been burnt there. However, it is difficult to lead the gases entirely into the combustion column or burners and to completely burn them, because they are not evaporated evenly at an equal amount throughout the length of the furnace in which they are heated, and additionally because the gases which are generally oily, are sticky. Such sticky gases tend to adhere to the inside of pipes and to furnace walls, becoming soft or molten. They change finally into a heap of ashes which disturb combustion and erode the furnace walls.
In this view, it is an object of this invention to provide a method, in which gases evaporated from articles heated in a furnace are smoothly led into burners located inside the furnace, whereby the gases do not stay long in the furnace and consequently do not erode the furnace walls. And, it is another object of this invention to provide a heating furnace which can advantageously perform the method.